Now for the snags.
Stud size is different (smaller) - diff works need to re-stud.
Brakes are 9½" or something - not so easy to get bits for.
Centre boss is larger than XK-XB wheel centre hole.
Centura diff is about ½" wider overall than a Falcon diff. The Falcon brake backplates are offset slightly more inwards, so changing to Falcon drums (or discs) means you can move the wheel bearing shoulder about ¼" each side.
You already have a later Falcon diff drained of oil, right? The brake flanges are pressed on, then welded. Remove the axles and backing plates, then stuff a good wad of clean rags into each tube. Carefully sawing through the weld at the flange end, then grinding, will allow recycling of the brake flanges. You can do this by hand, over a couple of cold ones. Measure, check and then cut the tubes to the new length, allowing for the part you won't see. File a little chamfer on the cut end.
New spring pads are easily bought off the internet, as I mentioned before. All XR-on except commercials, have the oversized oval hole in the spring pad - you don't realy want that so hence the need for new pads.
All the unwanted stuff can be trimmed off the donor diff with an oxy or grinder. Takes a little while (couple of hours), but your evenings and Sundays are free, right? Grind to a hair proud and hand file along the tubes to finish. Avoid excessive spot heating whilst cutting/grinding, by moving the disc around various areas.
Now see how much the diff guy will charge to position and weld the new pads, reattach the flanges, and press the diff straight.
I have an ongoing issue with subcontractors. They often like to do things
their way, which is the way that suits
them the most. However, it may well not be the best way for you.
Caveat emptor.
Good Luck.
